How To Monitor Tree Restoration
Where are all those trees growing?
A Short Summary
There is no debate: People need to restore the world's degraded land by growing trees and transforming farms, forests, and pasture into more productive ecosystems. That's how we can produce more food, safeguard biodiversity, and store carbon. But to know where we're going, we need to know where we have been. We need to track progress toward our goals, but that's not as simple as it may sound.
This guide showcases the latest advances in monitoring from World Resources Institute's Global Restoration Initiative . You will find examples of our work on individual tree-growing projects, across landscapes and countries, and globally.
If you are someone actively restoring land, we hope that this inspires you to invest in showing the impact of your work. If you are funding restoration, we hope that you will gain a new appreciation for this challenge and recognize why measuring progress is key to success. And if you are a researcher working in this field, we hope you can join us in tackling some of our remaining questions.
To sum it up, think of this as our effort to track our own progress toward answering a tough, yet important question: How much land are people restoring?
This is a February 2022 update of a storymap originally published in October 2020. Twice per year, the team at WRI revisits this article and adds the latest information.
Land in Makueni County, Kenya. Credit: Peter Irungu/WRI
Why Restore Land?
Degraded land threatens the well-being and livelihoods of over 3 billion people in nearly every country. Almost half of Earth’s forests have already been cleared or degraded to make way for agriculture and other human uses, leading to food insecurity, poverty, biodiversity loss, soil erosion, water pollution, and a host of other environmental, social, and economic challenges.
Right: Degraded hillside in Kenya's Makueni County. Credit: Peter Irungu/WRI
To better understand the extent of degraded land globally and where there is opportunity to improve it, WRI, IUCN and partners produced the Atlas of Forest and Landscape Restoration Opportunities, which found that 2 billion hectares of land could benefit from restoration (right).
From growing trees on farms to reforesting bare patches of land, forest and landscape restoration activities all share one common vision: Making land work for people and nature; creating opportunity while safeguarding biodiversity. Protecting and restoring land also has major climate benefits. According to the IPCC, healthy land removed a net 6 gigatonnes (Gt) of CO2 per year from 2007 to 2016, equivalent to the annual greenhouse gas emissions of the United States. And research shows that for every $1 invested, restoration can bring up to $30 in economic benefits because it:
People have recognized that opportunity. In 2011, governments and civil society banded together to launch the Bonn Challenge (strengthened by the New York Declaration on Forests in 2014), whose members have now pledged to restore more than 210 million hectares of land around the world, an area more than half the size of India. Through regional alliances like AFR100 in Africa, Initiative 20x20 in Latin America and the Caribbean, and ECCA30 in Europe, the Caucasus and Central Asia, countries have redoubled their efforts to invest in restoration.
In 2020, the private sector added its clout to this global effort to protect and restore land through the Trillion Trees initiative and corporate alliances like the Priceless Planet Coalition. Their goal is to invest in tree-growing projects to suck climate-warming carbon dioxide from the atmosphere, which could keep global heating below 1.5 degrees C (2.7 degrees F), the level the Paris Agreement says is needed to avoid the most damaging effects of a changing climate.
Following this momentum, people working on the ground across Africa, Asia, and Latin America have seen progress – from higher crop yields and more jobs to improved habitat for biodiversity – first-hand (like in Ethiopia, at right).
We have accumulated a tremendous amount of ad hoc evidence about the extent of this work around the world, but there is a key (and troubling) question we can't yet answer: How much land is actually under restoration?
Right: Planting trees in Ethiopia. Credit: Aron Simeneh/WRI
Why Track Progress?
"Without good data, we're flying blind. If you can't see it, you can't solve it." - Kofi Annan, former Secretary-General of the United Nations
Tracking restoration helps governments, companies, and NGOs show progress on their pledges, encourages people to replicate successful projects and tweak struggling ones, and inspires funders to continue investing where they can see positive results.
Measuring progress can also put the spotlight on farmers and others who have restored their land using a grassroots approach. Across the dry Sahel, for example, farmers have restored millions of hectares of land, boosting crop yields and stopping the southward creep of the Sahara Desert. But the lack of accurate data can further the misperception that drylands are treeless wastelands “degraded” by local communities. These stories and the lessons they hold can't be shared unless people can systematically identify and measure changes in the landscape.
As a member of the UN Decade on Ecosystem Restoration ’s task force on restoration monitoring and co-chair of the Global Restoration Observatory, WRI is fully engaged in this challenge.
Right: The Gran Chaco dry forest in in Paraguay. Credit: Ryan Sarsfield/WRI
The challenges of monitoring restoration
Thanks to platforms like Global Forest Watch and Resource Watch , we are getting better at seeing where deforestation is happening. However, the stark footprint of deforestation is, by comparison, much easier to see on satellite imagery than a tiny sapling slowly growing in a field (or other approaches to land restoration).
Most current large-scale pledges will rely on tree-based approaches for land restoration. Growing trees to maturity takes time, often 15 years or more. And the lower-resolution tree cover datasets that programs like Global Forest Watch (at right) have difficulty picking up subtle changes in the landscape or shifts in tree cover outside of dense forests.
To overcome these data limitations and challenges, we are investing in both improving existing data sets and exploring new methods that can more accurately detect trees in a variety of landscapes. Currently, along with the GLAD Lab at the University of Maryland, we are working on developing updated tree cover gain and loss data and improving its accuracy.
The latest advances
In October 2021, WRI also released preliminary tree cover data showing where billions of these trees — previously invisible to governments, investors and the public — are growing across 1.4 billion hectares of Africa and Latin America (an area 40% larger than the entire United States). Older tree cover gain datasets have trouble detecting trees outside of forests. New techniques are improving past work, especially in dry places with sparse tree cover, like Africa's Sahel. Our “trees in mosaic landscapes” data, which can be explored at right, combines high resolution satellite imagery and machine learning approaches to pick up more trees than ever before. Learn more in the short video explainer below.
Land and Carbon Lab: Trees in Mosaic Landscapes Data
Further improvements are on the way. In 2022, we expect the data to detect trees outside and inside forests across Africa, Latin America, South Asia and Southeast Asia’s tropical, subtropical and southern temperate zones. This would more than triple coverage from 1.4 billion hectares to nearly 5 billion hectares.
By 2023, the data would detect changes in tree cover in each 10-meter-by-10-meter plot between 2017 and 2022. We could even produce accurate maps that show annual change within that five-year span and that automatically identify monoculture tree plantations within pilot countries.
With all of the complexity and uncertainty, the task of monitoring restoration may sound daunting. But we are addressing these challenges and building a comprehensive vision with clear entry points for people restoring land. Our core goal is to improve access to accurate data for decision-making.
Our Vision
There is no one-size-fits-all solution to monitoring restoration: Different scales have different objectives and need different data. That's why WRI is working at three scales – project, landscape and global – to meet these needs while bringing them together into a holistic framework. Thanks to partners like FAO, Climate Focus, IUCN, NASA, Restor, and University of Maryland, we're getting farther.
In the next sections, we will unpack this vision and lay out how people restoring land and their allies can accurately and effectively track progress.
Right: A landscape in Tigray, Ethiopia. Credit: Aron Simeneh/WRI
For Projects
Who is it for? Project funders, project developers, companies, local communities
What is it? Project-level restoration monitoring is about measuring progress within a specific project boundary.
Thousands of restoration projects exist around the world, but the major challenge is knowing how effective they are and how to track them in an independent, systematic way.
National forest cover datasets and global approaches often focus on measuring intact and dense forests and typically do not track trees on farms, pasture, and settlements, even though most restoration happens in rural agricultural landscapes (outside of forests). This has created a large data gap, where millions of hectares of land under restoration are not captured in national or global statistics. Restoration there goes undetected and unrecognized.
We also need to make sure that the thousands of individual projects are part of a well-supported community of practice, where consistent, independent monitoring protocols are in place to support both project implementers and funders. This approach also needs to be adaptable to the local context and overarching goals of the project (which can sometimes involve cutting down some trees for timber).
To fill this gap, WRI is applying the trees in mosaic landscapes data to enable accurate reporting of tree cover in settlements, on agricultural lands, and in dry forest ecosystems. You can see how this data, accurate for each ten-by-ten-meter plot, is helping us see billions of scattered trees, from the drylands of Africa's Sahel (at right) to the open forests of Latin America.
This new data can reduce the need for expensive field verification visits to certify restoration projects. The methodology is open-source and relies on freely accessible satellite imagery, making it an affordable and cost-effective option for gathering tree cover data at the project scale.
This approach also allows us to track tree cover change over time. Now, we can more accurately measure where trees are growing within individual projects and across the surrounding landscapes. You can see an example of tree cover gain in São Paulo State, Brazil between 2017 and 2019 (right). In 2022, we will expand the trees in mosaic landscapes data to detect tree cover gain and loss across the world’s tropical, subtropical, and southern temperate zones, with the vision of updating that data every year.
Right: Tree cover gain (purple) measured from 2017 to 2019 on a 120-hectare native species plantation (in white outline), as well as the natural succession of saplings on oxbow lakes (at bottom).
We are using this data on TerraMatch , a platform that connects serious funders with experienced tree-growing projects, to provide projects a central place to show their progress. TerraMatch monitoring combines the trees in mosaic landscape data with consistently collected field data on social and environmental outcomes that project teams directly upload.
One hundred of Africa's leading project developers and entrepreneurs will use these techniques to monitor the impact of the grants and loans that they will receive through TerraFund for AFR100 . This living laboratory will provide both a testing environment for our approach and help us track the impact of restoration projects at a lower cost for locally led organizations.
TerraMatch combines satellite monitoring (left) and project reporting (right).
This mix of remote sensing, self-reporting, and local verification shows that funders that their work is having impact and provides project developers the opportunity to produce attractive digital reports that prove their expertise.
The road ahead: WRI is continuing to test these new techniques with technical experts and project developers and has synthesized those insights into a comprehensive project monitoring framework, developed with Conservation International. By testing that protocol in the field with the Priceless Planet Coalition, we will have a better understanding of how we can match high-quality satellite data with on-the-ground insights.
For Landscapes
Who is it for? National and sub-national governments, NGOs, regional initiatives
What is it? Restoration works best when people living in a landscape and their allies work together to set clear goals, like increasing crop yields or protecting water sources. A “landscape” can be a watershed, region, or even an entire country. Landscape-level monitoring is about measuring progress toward those goals.
Choosing those goals and designing a system to measure progress isn't easy, though. With the FAO, WRI has developed a guide, the Road to Restoration , that helps people understand the current state of the landscape, identify what they want to achieve (see below), choose the indicators that they need to prove success, and develop an actionable strategy for tracking progress toward their goals.
Through many test drives in Latin America, WRI and FAO turned the guide into an interactive decision support tool, AURORA , that helps stakeholders have an organized discussion on objectives, indicators, baselines, and targets that are needed to monitor progress toward their set goals.
The sheer volume of useful restoration monitoring approaches, though, can confuse people restoring land when they most need clarity. Below is a multi-step process that charts a clear path forward.
Following that rough path, WRI has co-created several custom monitoring systems that reflect the priorities and preferences of partners. In the following section, we highlight work we have supported in 6 countries around the world.
Right: An example of a mosaic landscape of agroforestry and natural forest stands in Ethiopia. Credit: Aaron Minnick/WRI
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1
India
India has made multiple national and subnational commitments for reversing land degradation, which includes restoring 26 Mha of land under the Bonn Challenge. To help meet its restoration and climate commitments, WRI India developed the Restoration Opportunities Atlas , which identifies nearly 140 Mha of opportunity for forest protection and landscape restoration. In the Sidhi District of Madhya Pradesh, the team is building a participatory monitoring architecture to track the restoration of more than 300,000 hectares. Citizen scientists within the local communities will collect progress data with a user-friendly app. The latest remote sensing techniques will supplement that field-collected data, and updates will be transparently featured on the Atlas.
2
Indonesia
Indonesia committed to restore 2 Mha of peatlands to heal soil, protect fresh water sources, sequester carbon, safeguard biodiversity, and create sustainable livelihoods. WRI Indonesia and partners created the Peatland Restoration Information and Management System (PRIMS) to track where this unique ecosystem is recovering, monitor the water table, and predict fire risk. In tandem, WRI’s Pantau Gambut (Peatland Watch) platform uses the power of communication and social media to mobilize public awareness and interest in restoration.
3
Brazil
To measure Brazil’s progress toward its Paris Agreement commitment to restore 12 Mha of forests, the Brazilian Coalition on Forests, Climate and Agriculture launched the Brazilian Restoration and Reforestation Observatory , with support from WRI. The platform brings together existing restoration data from regional alliances like the Atlantic Forest Restoration Pact to provide reliable, standardized information on progress. One highlight: The initial results show that nearly 11 Mha are naturally regenerating across the country.
4
Ethiopia
Ethiopia’s Environment, Forest and Climate Change Commission is leading an initiative to monitor tree restoration and its contributions to social and environmental goals. This builds off previous work done to map priority areas for restoration nationally.
To complement the monitoring of trees inside and outside forests already taking place, a Collect Earth Tree Assessment Survey was developed to collect data from very-high-resolution images available on Google Earth for four indicators: land use/land cover, tree cover, spatial distribution of trees, and percent linear features (e.g., roads, rivers) with tree canopy. This survey was recently piloted in two districts and is continuing to be tested around the country, now led by Wondo Genet University.
5
Kenya
As part of AFR100, Kenya pledged to restore 5.1 million ha of land after WRI and partners helped the Government assess which land could benefit from restoration. The Kenya Water Towers Agency , charged with protecting the country's water supply, convened 17 institutions and government agencies to build a system to track where growing trees in key watersheds can protect the livelihoods of more than 50 million people. They estimated forest cover change for each water tower between 1990 and 2016 based on Landsat 30-meter resolution data. Learn more here .
6
Malawi
Malawi was the first country in Africa to develop a National Forest Landscape Restoration Strategy , which links its restoration targets with development goals such as improving food security and reducing poverty. To track progress toward the strategy, WRI helped the government to design a monitoring framework , which identifies the indicators and metrics that are best-suited to show where restoration is successful or where more investment is needed.
7
El Salvador
El Salvador was the first country to join the Bonn Challenge , when it pledged to restore half of the country. To track progress, WRI, with GIZ and under the leadership of the Ministry of Environment and Natural Resources, designed and implemented the Sustainability Index for Landscape Restoration, the first monitoring system for landscape restoration in Latin America. Crucially, the Index is housed in a public reporting platform that anyone can access.
The road ahead:
Having strong data, innovative tools, and robust plans is important, but they are of little use unless the stakeholders have the capacity to act on them. WRI is continuing to help governments, independent monitors, and local organizations integrate high-quality data into their monitoring work. Supporting regional initiatives like Brazil's Atlantic Forest Restoration Pact to measure progress will help them celebrate early wins and tweak struggling projects within their landscapes. Integrating social data, e.g. on gender and inequality, into this work will also help leaders break through the barriers to success.
Building up capacity within local institutions and universities through targeted trainings, and making sure that the data that is co-produced and locally owned, will be key to tracking restoration progress across hundreds of landscapes. To that end, WRI is developing a "monitoring accelerator," where cohorts of technical staff from government agencies and leading project developers can explore how the latest advances could help them. In that collaborative setting, they can exchange past experiences and help solve each other's problems.
Globally Consistent Data
Who is it for? Investors and donors, international NGOs, national governments, and the informed public eager for proof that restoration works.
What is it? Land degradation is a global crisis. Major international initiatives like the Bonn Challenge, AFR100, Initiative 20x20, and the Trillion Trees platform were established to scale up and support national restoration efforts. Monitoring those commitments requires globally-consistent datasets, which enable us to compare progress across countries and measure change globally.
In 2021, the most exciting recent developments are new ground-breaking datasets on forest height change and trees in mosaic landscapes, which were released at the UN climate meeting COP26, as part of WRI’s Land & Carbon Lab .
The forest height data, produced by the University of Maryland, is the first dataset that measures net change (both gain and loss) of forests around the world. While tree cover loss has been well-documented on Global Forest Watch since 2014, tree cover gain has been more difficult to monitor using traditional methods. The new algorithms that combine multiple satellites, like Landsat and GEDI, can provide a pixel-by-pixel count of forest height change from year to year at 30-meter resolution.
The new trees in mosaic landscapes data , explored above, provides a finer-resolution measurement of tree cover outside of dense forests. On these croplands, across pastures, and in urban areas, we can now see trees that were previously invisible to satellites and excluded from forest cover estimates. The hard work is now on us to analyze and process these new datasets to better understand net changes in tree cover and how they can inform our work tracking global restoration commitments. Fortunately, we are well on our way.
These kinds of datasets, when carefully combined, can provide a comprehensive assessment of tree cover gain and loss. For example, by employing data from the University of Maryland GLAD Lab (for trees inside forests) and Collect Earth mapathons (for trees outside forests), WRI produced the first-ever independent assessment of tree cover gain and loss across a region. This analysis showed where trees are growing both inside and outside the Mekong region's forests (at right).
Today, we have taken the first steps toward designing a global tree restoration monitoring system that can assess net tree cover change every year. Our goal is that is this work will help national and subnational governments track progress toward their commitments to the Bonn Challenge, AFR100 in Africa, and Initiative 20x20 in Latin America and the Caribbean.
The road ahead: As part of the Global Restoration Observatory, we are working with WRI’s international offices, in-country partners, and leading research institutions to develop a global restoration monitoring system that will measure and compare restoration progress around the world.
In 2022, we are testing the preliminary tree height change dataset from the GLAD Lab (at right). The initial results are promising, helping us show the dynamic nature of tree cover: the patchwork of gains and losses at 30-meter resolution. We are also constantly improving the trees in mosaic landscapes data, explored above, by expanding its geographic scope and investigating its applications for detecting annual tree cover change in every 10-meter-by-10-meter plot.
By associating the tree height change and trees in mosaic landscapes datasets with ever-improving carbon sequestration data, we are working toward a less expensive, globally consistent method for tracking the carbon-storing potential of the world's trees, both inside and outside dense tropical forests.
A Path Forward
Monitoring tree restoration and its associated benefits has never been done. To get it right requires trial and error, testing many data and methods, learning from partners, and building a community of practice. With this new momentum spurred by corporate pledges, platforms like TerraMatch , and the latest scientific advances, now is the time to start investing in tracking progress.
It's time for a comprehensive vision for monitoring that is built on independent data and that does more than identify areas that could potentially benefit from restoration. With partnerships like the Global Restoration Observatory, led by Climate Focus, and through the FAO and UN Environment-led UN Decade on Ecosystem Restoration , WRI is building systems and approaches – a kind of “Restoration Watch” – that help governments, project developers, and funders track progress accurately at all scales.
This online system will link with the new Land & Carbon Lab , which will leverage satellites and other cutting-edge technologies to measure land use change and its associated carbon emissions. The initiative, which includes the monitoring data highlighted here, will provide communities, governments, investors, and NGOs with high-quality data to help them measure the impact of nature-based solutions to the climate crisis.
Monitoring biophysical change isn’t enough. We also need to invest more in measuring the social impact that restoration can have, particularly on marginalized communities and women. To start, mapping the social landscape , the networks of finance, power, and information that govern people's lives, can provide us a baseline understanding of the social relations that make restoration possible (or stop it in its tracks). While the social dimension is complex, it is also the root of the restoration movement – bringing positive change to people’s lives. Now, we are seeking experienced partners to help us associate the latest biophysical data with socioeconomic data collected from the field. One thing is clear: Only by balancing ecological, social, and economic goals will the restoration movement succeed.
Our methods won’t answer every question, but we have forged a path ahead and are eager for collaborators to join us on the journey. Together, we can answer the key question that funders and implementers ask: How much land is under restoration?
We know that people can build stronger economies and healthier land. Tracking progress can help them prove that investing in restoration is a win for local people, governments, and companies.
Thanks for reading! Questions? Reach out to restoration.monitoring@wri.org
Right: A restored landscape full of trees in Nicaragua. Credit: James Anderson/WRI
